Abstract

Background

Concerns have been expressed about the impact that screening for risk of
suicide may have on a person’s mental health.

Aims

To examine whether screening for suicidal ideation among people who attend
primary care services and have signs of depression increases the short-term
incidence of feeling that life is not worth living.

Method

In a multicentre, single-blind, randomised controlled trial, 443 patients
in four general practices were randomised to screening for suicidal ideation
or control questions on health and lifestyle (trial registration:
ISRCTN84692657). The primary outcome was thinking that life is not worth
living measured 10–14 days after randomisation. Secondary outcome
measures comprised other aspects of suicidal ideation and behaviour.

Results

A total of 443 participants were randomised to early (n = 230) or delayed
screening (n = 213). Their mean age was 48.5 years (s.d. = 18.4, range
16–92) and 137 (30.9%) were male. The adjusted odds of experiencing
thoughts that life was not worth living at follow-up among those randomised to
early compared with delayed screening was 0.88 (95% CI 0.66–1.18).
Differences in secondary outcomes between the two groups were not seen. Among
those randomised to early screening, 37 people (22.3%) reported thinking about
taking their life at baseline and 24 (14.6%) that they had this thought 2
weeks later.

Conclusions

Screening for suicidal ideation in primary care among people who have signs
of depression does not appear to induce feelings that life is not worth
living.

Suicide is a major cause of premature mortality, which results in over 1
million deaths worldwide per
year.1 Previous
research demonstrating high levels of contact with primary care in the period
prior to completed
suicide2–
4
has highlighted the role that such services might play in efforts to reduce
the incidence of
suicide.5 A central
component of guidelines for the assessment and treatment of depression in
primary care is asking patients about suicidal ideas and
intent.6 Despite the
emphasis placed on screening for risk of suicide among people with signs of
depression, studies have found low levels of assessment among people treated
in primary
care.7–
9
Reasons for this include concerns about the impact on patients of being asked
such
questions.8,
10
In a vignettes-based study of 170 general practitioners (GPs) in Germany, 1 in
5 stated that they would not assess suicide risk among elderly patients with
depression because they feared that asking such questions could ‘
induce’ suicidal thoughts and
behaviour.11 A more
recent survey of GPs in England revealed that a quarter believed that
screening for suicidal ideation could induce a person to have thoughts of
self-harm.12
General practitioners that took part in this study stated that young people
and those with personality disorder may be especially susceptible to the
effects of being asked such questions.

Support for the notion that suicidal ideation can be ‘
transmitted’ by exposure to this subject comes from observational
studies showing clustering of suicidal behaviour on in-patient mental health
units13 and
short-term increase in the incidence of suicidal behaviour following media
coverage of incidents of
suicide.14–
16

It has been argued that before screening for health-related problems is
introduced, the potential harms as well as potential benefits need to be
examined.17 The
impact of screening for suicidal ideation among people with signs of
depression in primary care has not been examined. An official inquiry into
methods for preventing suicide in the USA concluded that, for this reason,
screening for suicide risk in primary care could not be
supported.18 In the
light of the uncertainty about the impact of screening for suicidal ideation
in primary care, we set out to conduct a clinical trial among people who have
signs of depression and are treated in this setting. Our primary aim was to
find out whether being screened for suicidal ideation had a short-term impact
on the extent to which patients subsequently felt that their life was not
worth living.

Method

We conducted a randomised trial (trial registration: ISRCTN84692657) among
people attending primary care services in north and west London. We recruited
study participants from four practices where we had established links with
local clinicians. The practices are all in inner-city areas that have a
relatively young and ethnically diverse
population.19 The
practices each serve between 7000 and 9000 local residents. Recruitment took
place over a 22-month period (March 2007 to December 2008).

Study procedures

People registered with these practices who were aged over 18 were screened
for depression using a two-item screening questionnaire (‘During the
past month, have you often been bothered by feeling down, depressed or
hopeless?’ and ‘During the past month, have you often been
bothered by little interest or pleasure in doing
things?’).20

Those who responded ‘yes’ to either or both items were given
written and verbal information about the study and asked to provide consent to
take part. In most instances a researcher (P.B. or L.T.) asked the screening
questions prior to the clinical consultation. In a minority of instances,
clinical staff working in the practice used the screening questions during the
clinical consultation or as part of routine health checks.

Potential participants were told that we were conducting a clinical trial
that aimed to find out how people respond to being screened for ‘health
and emotional problems’ – no mention was made of depression,
suicidal thoughts or behaviour. Those who agreed to take part in the study and
had sufficient command of English to complete the baseline interview were
randomised to screening for suicidal ideation or questions on health and
lifestyle. We used simple randomisation based on a central computer-generated
list. All study participants were interviewed on the telephone on two
occasions separated by between 10 and 14 days. During the first of these
interviews, which was usually conducted by the researcher that recruited the
participant (P.B. or L.T.), we repeated the two-item screening questionnaire
for depression, collected basic demographic data and assessed
participants’ mental health using the 12-item General Health
Questionnaire
(GHQ).21 A score of
three or more on this questionnaire is taken to indicate
caseness.22 In
addition, participants were asked six further questions on either suicidal
ideation and behaviour or health and lifestyle depending on their allocation
status.

Questions on suicidal ideation and behaviour were based on those widely
used in previous studies examining public mental
health23–
25
which have been recommended as helpful for assessing suicide
risk.26 They were: ‘
In the last 2 weeks: Have you felt that life was not worth living? Have
you wished that you were dead – for instance, that you would go to sleep
and not wake up? Have you thought of taking your life even if you would not
really do it? Have you seriously considered taking your life? Have you
attempted to take your life?’ We also asked participants about exposure
to suicidal behaviour among people close to them as this has been highlighted
as an important factor to consider when assessing for risk of
suicide.26 We asked
participants: ‘Has any member of your family or someone else you are
close to attempted to harm themselves or commit suicide in the past?’
Control questions on diet and lifestyle were taken from the Preventive
Nutrition
Project.27

All follow-up interviews were conducted by a different researcher who was
masked to the participant’s allocation status. On this occasion all
participants were asked the six questions on suicidal ideation and behaviour.
In response to concerns expressed by some healthcare professionals that people
with personality disorder may be susceptible to negative effects of screening
for suicidal
ideation,12 we used
an eight-item screening tool to assess personality (the Standardised
Assessment of Personality – Abbreviated Scale,
SAPAS).28 We used a
cut-off point of three or more on the SAPAS to indicate ‘probable
personality disorder’. Finally, we asked four questions on social
support taken from the Close Persons’
Questionnaire.29

When participants described thoughts that life was not worth living the
researcher made further assessment of suicide risk, encouraged the person to
make use of resources already available to them (such as discussing their
feelings with healthcare staff), and provided information about helplines and
other sources of help. In rare instances where participants reported suicidal
plans, the researcher asked for verbal consent to contact clinical staff on
their behalf. Brent Medical Ethics Committee approved the study prior to the
start of data collection (06/Q048/73).

Sample size

Data from a previous population-based study of mental health in England
suggests that 31% of people who have evidence of depression have thought that
life was not worth living during the previous
week.25 In order to
have 80% power and 5% level of significance to detect an increase in the
proportion who felt their life was not worth living from 30 to 45%, we needed
to recruit a sample of 326 individuals. To take account of the clustered
nature of the study sample and in anticipation of 15% loss to follow-up we
increased the sample size to 429 participants.

Data analysis

All analyses were based on the intention-to-treat principle using a
complete case analysis. Simple descriptive statistics were used to examine
differences in the characteristics of those randomised to screening for
suicidal ideation or questions on health and lifestyle. Differences in primary
and secondary outcomes were examined by calculating odds ratios (OR) with 95%
confidence intervals (95% CI). To identify factors associated with feeling
life was not worth living during the follow-up interview, we used hierarchical
logistic regression. All potential confounders (both demographic variables
such as age and gender and clinical factors such as mental health) and
interaction terms were included in the first step. The non-significant terms
were eliminated one by one until the final model was obtained. The statistical
methodology used in the analysis took account of the hierarchical structure of
the data: people nested within general practices. This was an important
consideration since we expected people from the same service to have more in
common than people from other services. This analysis was carried out by
gllamm, a programme written in STATA for Windows, version 10.

Results

The trial profile is shown in
Fig.
1. In total, 443 people were recruited. Their mean age was 48.5
years (s.d. = 18.4, range 16–92), 137 (30.9%) were male and 191 (43.1%)
participants were married or in long-term relationships. Of the 421 that
provided information about employment status, 201 (47.7%) were working or in
training, 134 (31.87%) were unemployed and 86 (20.4%) were retired. All
participants scored at least one out of two on the two depression screening
questions, with 255 (57.6%) scoring positively on both. Mean score on the GHQ
was 5.5 (s.d. = 3.6), with 278 (62.8%) meeting threshold for psychiatric
caseness. Overall, 213 participants were randomised to screening for suicidal
ideation and 230 to control questions. There were no deviations from random
allocation, and data on one person (aged 16) who was erroneously randomised
were included in the analysis. Baseline characteristics of those randomised to
each arm of the trial are presented in
Table 1.

Follow-up data were obtained on the primary outcome measure for 351 (79.2%)
participants. Characteristics of those who were and were not followed up at 2
weeks are presented in
Table 2.
Demographic characterises and mental health of those who were and were not
followed up appear to be similar.

Baseline characteristics of participants who did and did not provide
follow-up data on primary outcome measure

At the 2-week follow-up interview, 46 (28.0%) of those randomised to
screening for suicidal ideation and 45 (24.1%) of those randomised to control
questions reported feeling that their life was not worth living (OR = 1.23,
95% CI 0.76–1.98). Of those randomised to questions on suicidal
ideation, 38 (23.2%) reported wishing they were dead compared with 43 (22.9%)
of those randomised to questions on health and lifestyle (OR = 1.01, 95% CI
0.61–1.66). Of those screened for suicidal ideation, 24 (14.7%) reported
having thought of taking their life compared with 21 (11.3%) asked questions
on health and lifestyle (OR = 1.36, 95% CI 0.72–2.54). One person who
was randomised to control questions reported having attempted to take their
life at follow-up; no one among those randomised to screening for suicidal
ideation reported having done so.

Among those who were randomised to baseline screening for suicidal ideation
and followed up, 37 (22.5%) of 164 people reported thinking about taking their
life during the previous 2 weeks. Of 164 participants, 24 (14.6%) reported
thinking about taking their life 2 weeks later, and 5 (3.9%) of 129 people who
denied thinking about ending their life at baseline reported thinking so
during the 2 weeks after screening. In contrast, 17 (45.9%) of the 37 people
who had thought about ending their life at baseline denied having this thought
at follow-up.

Factors associated with feeling life was not worth living adjusted for
clustering at the level of general practice are presented in
Table 3. The odds of feeling
that life was not worth living among those screened for suicidal ideation
compared with those asked questions on health and lifestyle was 0.88 (95% CI
0.66–1.18). In this model, the thought that life was not worth living at
follow-up varied between the four general practices and was strongly
associated with baseline mental health and the presence of probable
personality disorder. Associations between the primary outcome with age and
level of social support were not found. An interaction between being
randomised to screening for suicidal ideation and employment status was found,
suggesting that among those who were screened at baseline, suicidal ideation
at follow-up was less likely among those who were retired compared with those
who were unemployed. Interactions between personality status and age and the
impact of being screened for suicidal ideation during the baseline interview
were not found.

Factors associated with feeling life is not worth living among 351
study participants who completed follow-up interviews

Discussion

Our findings confirm that many people who have signs of depression and are
treated in primary care experience suicidal ideation. More than 1 in 8 people
who took part in the study reported that they had thought of taking their life
during the previous 2 weeks, although fewer than 1 in 20 reported having given
serious consideration to ending their life. We found no evidence to support
the view that screening for suicidal ideation among people in primary care
leads to an increase in feelings that life is not worth living.

Strengths and limitations

The main strengths of the study were that it was randomised and that
researchers collecting follow-up data were masked to allocation status. By
focusing on people who had signs of depression, we included those patients for
whom screening for suicidal ideation has been
recommended.6 We
focused our collection of follow-up data on the first 2 weeks after screening
because data from observational studies suggest that if increases in suicidal
ideation were to be found it would be within this
period.14

There are four main limitations associated with the study design. First,
although we achieved the study sample we aimed to recruit and this was
sufficient to detect clinically important differences in thoughts that life
was not worth living, the power of the study was insufficient to explore
differences in subgroups of patients, or to detect differences in other
aspects of suicidal ideation or behaviour. With an incidence of 3 per 1000 in
the 2-week period that we studied, we would have needed to have randomised
over a million people to have had sufficient power to examine differences in
the incidence of self-harm during this period. However, feelings that life is
not worth living provide a sensitive (if not specific) indication of those at
increased risk of suicidal
behaviour24 and we
believe that this outcome provided a sensitive measure of the potential impact
of screening on the emotional health of study participants.

Second, we could not collect baseline data on levels of suicidal ideation
or behaviour among those randomised to questions on health and lifestyle, as
to do so would have undermined the central aim of the study. As a result, we
do not know whether levels of suicidal ideation differed between study groups
at baseline. However, we were able to assess general mental health, a factor
which was strongly associated with suicidal ideation, and we believe that the
adjusted odds ratios we have presented therefore provide a more accurate
estimate of the true relationship between screening and future suicidal
ideation.

Third, study participants were all recruited from relatively deprived
inner-city practices. Almost 40% of adults of working age that took part in
the study were unemployed. Although we have no reason to believe that
screening for suicidal ideation would be associated with different outcomes
among people living in less deprived areas, we cannot be certain of this.

Finally, the method we used to screen for suicidal ideation in the study
differed from the approach that would normally be taken in clinical practice.
Interviews with participants were conducted on the telephone after their visit
to the GP rather than face to face as part of a clinical consultation.
Although the external validity of the study would have been greater if
participants had been asked about suicidal thoughts during the session with
the doctor, GPs told us that it would be impractical for them to randomise
patients during the clinical consultation.

Clinical implications

This is the first time that the impact of screening for suicidal ideation
has been examined experimentally among adults. However, a previous attempt was
made to examine the impact of screening school-aged children for risk of
suicide using a self-completed
questionnaire.30
Two days after completing the survey, the mental health of those that had been
asked questions about suicidal thoughts was no worse than that of children who
had not been asked these questions. As with our study, confidence limits
around the odds ratio for suicidal ideation were broad (OR = 1.2, 95% CI
0.72–2.00), but sufficient for the authors to conclude that screening
did not increase the likelihood of such
thoughts.30

Although our findings have implications primarily for those working in
primary care settings, we believe that in the absence of evidence on the
impact of screening for suicidal ideation in general hospital settings, these
data have wider implications. Researchers investigating the epidemiology of
suicidal behaviour face a variety of ethical
challenges,31 and
concerns about the impact of assessing suicidal ideation in research projects
have been raised in the
past.32 Ethics
committees have expressed concerns about the impact of research participants
being asked such questions, and these findings may help reassure those
reviewing proposals for new studies that asking questions about risk of
suicide does not appear to have a short-term detrimental effect on
people’s mental health.

Among those who were randomised to screening for suicidal ideation, we
found that very few people who did not have thoughts of ending their life at
baseline reported having these thoughts at follow-up. In contrast almost half
of those who reported thinking of ending their life at baseline denied having
this thought during the following 2 weeks. These findings support those of a
population-based study by Gunnell and colleagues who found that most people
who experience thoughts of ending their life no longer do so 18 months
later.33 They also
provide support for the view that ‘watchful waiting’ of those with
suicidal ideation is appropriate in primary care, in the absence of firmer
evidence of risk of suicide such as a suicide
plan.6

Although these data provide evidence that screening for suicidal ideation
does not have an impact on the likelihood of subsequent suicidal ideation,
they do not provide information about how patients feel about being asked such
questions. For some healthcare practitioners and patients the topic of suicide
remains a sensitive
one10,
12
and such enquiry needs to be handled in a sensitive manner. Our data suggest
that when these questions are asked in such a manner they do not appear to
increase the likelihood of people starting to think their life may not be
worth living.

This study did not examined whether screening for suicidal ideation in
primary care leads to improved patient outcomes. Previous research examining
the impact of a primary care-based intervention following self-harm found no
evidence of patient
benefit.34 Further
research is required to examine the process and outcomes of screening for
suicide risk in primary care to establish the impact of current guidelines
which advocate this practice.

In summary, screening for risk of suicide does not appear to increase the
likelihood of a person having thoughts that life is not worth living. Primary
care workers should have the confidence to screen for suicide risk among
people with signs of depression.

Funding

The study was funded by an educational grant from Imperial
College London and supported by St Mary’s
Paddington Charitable Trust.

Acknowledgments

We thank Christine Lyons, Elena Borreani and Melissa Patel for their help
with data collection.